JPH0286345A - High-speed polling communication method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a polling communication method in which a timing signal is issued from a center to all terminals to communicate with terminals that have data, and the present invention is concerned with a polling communication method in which a timing signal is issued from a center to all terminals to communicate with terminals that have data. The purpose of this is to provide a high-speed polling communication method that allows the center to simultaneously send inquiry signals to all terminals.In response to the simultaneous polling, each terminal sends an inquiry signal in advance to each terminal only when there is response data. The configuration is such that a response is made at a specified delay timing, and then the center performs polling to include the terminal that received the response and performs normal data communication.

[Industrial application field]

The present invention relates to a boring communication system in which a center issues a timing ttS signal to all terminals to communicate with terminals that have data.

[Conventional technology]

Conventionally, when a large number of terminals are connected to one center, for example, a method of branching out terminals 1 to n as shown in FIG. 4 (α),
Alternatively, in the case of the continuous connection shown in FIG. 6 (6), a boring communication method is used as a communication method that does not have sufficient channel capacity on the center side.

That is, the center sequentially sends an inquiry (ENQ) to the terminals, and if there is a terminal that has data, it communicates with it. In this case, sending the ENQ is called polling.

In the conventional polling communication method, as shown in Figure 4 (6), the center sends an ENQ to all terminals 1.2...
If an ACK is obtained and there is p1 data, then this process is performed. For example, terminal 1 uses empty polling,
If there is data in the terminal 2, the data is processed and then transferred to the terminal 5. This process is repeated up to terminal n.

[Problem to be solved by the invention]

In the conventional polling method described above, the waiting time until a terminal with data receives a poll is not a problem when the number of terminals is small, but when the number of terminals is in the hundreds, the waiting time is considerable. and reduce system performance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-speed polling communication system that sufficiently reduces the waiting time of terminals that have data.

[Means to solve the problem]

In order to achieve the above objective, as shown in the main flowchart in Figure 1, simultaneous polling (2) is carried out in which the center simultaneously sends a timing signal to all terminals, and in response to the simultaneous polling, each terminal receives response data. Only if there is a terminal, a response (2) is made at a predetermined delay timing for each terminal, and then the center performs polling (2) to include the terminal that has responded, and normal data communication is performed.

[For production]

Although it is difficult to accurately identify the contents of the response (2) to the simultaneous polling (2) above, the general timing can be recognized. Therefore, data communication can be performed by performing polling from the previous terminal to include the terminal that received a 0 response. Therefore, most of the idle polling for terminals with no data can be omitted. Therefore, when there are many terminals, the overall speed can be increased even if the time for the first simultaneous polling (2) is included.

〔Example〕

FIG. 2 is an explanatory diagram of the operation of the embodiment of the present invention] and is a detailed explanatory diagram of a specific example with respect to FIG.

, In the figure, first, the center sends the same time alignment (ENQj) code ■ to all terminals 1 to %. Each terminal responds only to terminals that have data at the assigned sequential delay timing.

This time T is about 40 m5, for example, if the forward delay timing is 200 μa and there are 200 terminals.

Now, as shown in the figure, terminal 5. Assume that terminal n-5 has data, so there are responses ■ and ■. In this case, the terminal that does not have the data does not issue the response ■, and the center recognizes the responses ■ and ■, but only the timing, not the content, is recognized. But the timing at this time T! ? ! Since this information is not always accurate due to timing errors and line conditions, polling is started from terminal 2 in response to the response (2) so that target terminal 5 is always included.

Therefore, after empty polling of the terminal 20 ENQ (ENQ) and ACK (2), polling (ENQ2-1) (2) of the terminal 3 is performed, and data communication is performed following the ACK from the terminal 3.

For the next target terminal n-5K, polling is similarly started from the terminal n-4 ((1), (2)), and data communication is performed with the polling [shares] of the target terminal n-5.

Now, if we compare the time delay of terminal n-5 with the conventional one,
The s depth is 200, and the empty polling time is 5ms.

If the data is 52 m5, the conventional method is 32 + 3 x 195 times 617 m5 due to the empty polling of terminal 3, but in the present invention it is 40 + 3 + 32 - 75 times, and the waiting time can be significantly reduced. .

FIG. 3 is an explanatory diagram of the configuration of an embodiment of the present invention.

In the center 10 of the figure, there is a communication circuit 12 that outputs an availability code (ENQ) under the control of the CPU 11, and a terminal 201.
It has a communication switching circuit 13 that simultaneously or arbitrarily switches the communication lines to 20% and 20%, and connects the terminal (1
) 20t→20 units, and a response is made for each predetermined sequential delay time, for example, every 200 μs,
The response signal is input to the communication circuit 12.

In the above configuration, the CPU 11 instructs the communication switching circuit 13 to simultaneously poll all terminals, and
Inquiry CENQ) AND gate 141~1
411 to the terminals 201 to 20s K.

Each terminal that receives the ENQ and has data to send sends a response after the time determined by the terminal itself.

Setting of the time allocated to each of the terminals 201 to 20g& is performed as follows. Each terminal 201-20
% is provided with a switch group for setting the number of its own terminal, and the terminal number of its own terminal is set by the combination of on and off of each switch in this switch group, so each terminal 20. ~20%, the on/off state signals of each switch in the switch group provided in the own terminal are input to the arithmetic unit within the own terminal. This arithmetic unit multiplies the terminal number of its own terminal represented by the on/off signals of the input switch group by a predetermined constant value and outputs the result. This output value becomes the time allocated to each terminal mentioned above.

The CPU 11 that sent the ENQ monitors the received signal using the communication circuit 13, and if a signal is received, the timing is stored.

After the time specified for the terminal, the CPU determines from memory the approximate number of the terminal that responded, and, for example, starts polling from the terminal immediately before it, thereby minimizing the waiting time for data communication. can.

〔Effect of the invention〕

As explained above, according to the present invention, in conventional polling, because of the idle polling time for terminals that do not have data, as shown in the above example, especially in the case of a large number of terminals, terminals lined up after However, since the present invention is designed to eliminate this problem, the waiting time can be kept to a minimum and high-speed polling can be performed.

[Brief explanation of drawings]

Figure l1g1 is a flowchart of the main part of the present invention, Figure 2 is an explanatory diagram of the operation of the embodiment of the present invention, Figure 3 is a diagram explanatory of the configuration of the embodiment of the present invention, and Figures 4 (α) to (C) are This is an explanatory diagram of a conventional example.
In the figure, 10 is a center, 11 is a CPU, 12 is a communication circuit,
13 indicates a communication switching circuit, 141-14% & home AND gate, and 201-20% terminals. Flowchart of main parts of the present invention Fig. 1

Claims (1)

[Claims] Simultaneous polling is performed in which a timing signal is sent from the center to all terminals at the same time, and each terminal responds to the simultaneous polling at a predetermined delay timing, only when response data exists. A high-speed polling communication system characterized in that the center performs polling to include terminals that have responded and performs normal data communication.